This will be the second Gordon Research Conference on MOTILE AND CONTRACT SYSTEMS. The focus of the meeting will be the plasticity and assembly of contract systems: implications and significance for morphogenesis. It will include approximately 25 formal presentations by invited speakers with major emphasis discussion by invited and uninvited participants. The latter, especially, will encouraged to present posters of their work and one session will be devoted discussion of the posters. This format worked very well 2 years ago and we plan continue emphasizing a minimum of formal presentations to maximize both spontaneous exchange and the opportunity to introduce significant new observations. The conference will begin with a session (#1) on the assembly of cytoskeletal proteins; it will address the dynamic instability of microtubules and the recent demonstrations protein exchange in both thick and intermediate filaments. This will be followed by sessions (#2) on mitosis with emphasis on the analyses of spindle and chromosome kinetics with improved fluorescent labeling, digital imaging and electron microscopic immunolabeling procedures. The next session (#3) will address newly discovered cytoplasmic motors, their composition, physiological properties and analysis molecular genetics. Advances have recently been made in understanding the associate of cytoskeletal proteins with membranes; this will be the subject of one session (#4). We will next shift to the role of contractile and cytoskeletal proteins in each development. This session (#5) will focus on cortical inheritance and pattern formation, the role of the cytoskeleton in germ cell development and the recent demonstrated linkages between intermediate filament proteins, nuclear lamins ankyrin. Chemotaxis and directed cell migration will be examined in session #6 highlight macrophage, neuronal outgrowth and cellular slime mold systems. One session (#7) will be devoted to the regulation of nonmuscle motility with emphasis on linkages between second messenger systems and contractile protein activation. The molecular biology of contractile protein assembly will be the topic of session #8 and will focus on genetic systems in yeast, Caenorhabditis and Drosophila for examining microfilament assembly and myofibrillogenesis. Session #9 will be used for a review and discussion of the most noteworthy posters.